The Haemophilus influenzae type B vaccine, often called Hib vaccine, is a vaccine used to prevent Haemophilus influenzae type b (Hib) infection. In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis. It is given by injection into a muscle.Severe side effects are uncommon. About 20 to 25% of people develop pain at the site of injection while about 2% develop a fever.There is no clear association with severe allergic reactions. The Hib vaccine is available by itself, in combination with the diphtheria/tetanus/pertussis vaccine, and in combination with the hepatitis B vaccine, among others.All Hib vaccines that are currently used are conjugate vaccine. An initial Hib vaccine was developed in 1977 which was replaced by a more effective formulation in the 1990s.As of 2013, 184 countries include it in their routine vaccinations. (source)